聚萘酯聚集态结构的X射线衍射研究

本文由非晶聚2,6-萘二甲酸乙二醇酯(PEN)经不同的处理方法,制得了一系列不同结晶度和拉伸度的样品,并用X射线衍射方法研究了它们的聚集态结构。     

An estimate of the limit state of power transformers and autotransformers

The main indicators of the limit technical state of transformers and autotransformers, for which their further use is impermissible or inadvisable, are considered. The main elements of a power transformer which determine its limit state are the windings and the cores. Important indicators for estimating the technical state of the windings is the wear of the coil insulation, the degree of mechanical fastening of the windings and, in particular, the absence of dangerous deformations. Wear of the coil insulation is estimated from the degree of polymerization and the short-circuit resistance. The cores of the transformer become damaged fairly rapidly during operation. Normalized values of the above indicators are given as well as experience in using them in the Russian Federation and the Ukraine to estimate the limit state of transformers and autotransformers. The amount of inspection in order to reach conclusions on the technical state of a transformer and temporary measures until they are replaced are indicated. __________ Translated from élektricheskie Stantsii, No. 1, pp. 44–49, 2008.     

城市土地利用混合程度与居民出行空间分布——以南京主城为例

本文讨论了土地利用的混合程度与居民出行空间分布的相互作用关系，明确了城市片区的土地利用混合程度概念与计算模式，并通过城市土地利用、居民出行情况的调查数据与统计结果及趋势曲线，分析土地利用混合程度与居民出行空间分布的作用机理，构建片区土地利用混合程度与片区内部居民出行比例两者之间的关系模型。     

Moisture barrier and physical properties of acetylated derivatives with increasing acetylation degree

Four acetostearin products with increasing acetylation degree were synthesized by chemical interesterification followed by fractionation/blending stages. Their physical properties and functional barrier properties were studied and compared to the properties of technical tristearin. Increasing acetylation degree (AD) modified the triacylglycerols crystal habits and probably led to an increase in acyl chain fluidity, which induced, at macroscopic levels, a decrease in solid fat content (SFC), in melting point, in surface and bulk material hydrophobicity, and an increased moisture effective diffusivity. Water vapor permeability (WVP) coefficients of the materials were partially influenced by the AD factor, but also by the development of macroscopic cracks in lipids presenting high SFC. Acetylated stearin up to 47% (acetyl mol/mol of esterified chain) presented the lowest WVP at 20 °C resulting from an adequate balance between hydrophobicity and mechanical properties of the material.     

水泥混凝土路面施工质量控制水平的属性识别

选取弯拉强度变异系数、弯拉弹性模量变异系数、基层顶面当量回弹模量变异系数以及面板厚度变异系数等4个指标作为水泥混凝土路面施工控制水平分析评价指标,根据属性识别理论来解决水泥混凝土路面施工控制水平的识别问题。首先讨论建立单指标属性测度函数,其次讨论多指标属性测度的综合问题,然后讨论综合评价的属性识别准则,最后建立基于客观性权重的水泥混凝土路面施工控制水平识别的属性综合评价模型。研究表明,该评价模型是水泥混凝土路面施工控制水平评价的有效手段。     

石质文物风化程度的超声波CT检测

我国是一个具有悠久历史的文明古国，拥有大量的具有重要历史意义和价值的文化遗产，然而，由于长期的风化作用，导致它们损伤严重，亟须对其风化程度进行评价。超声波测试具有检测分辨率高，对被测物无损伤等特点，使其成为检测石质文物风化程度的有力手段。从理论和办法上，对运用超卢穿透波CT检测石质文物风化程度的方法进行了探讨，提出了一套利用超声波CT法检测现场石质文物风化程度和文物材料丰要力学参数分布状况的方法。利用这套方法对浙江省义乌市南宋古桥——古月桥桥身条石的风化程度进行测试，取得了较好的效果。     

混频器设计中的关键技术研究

混频器已经在诸多领域中得到了广泛的应用,其技术指标的好坏直接影响到整机性能的发挥。从混频器的基本概念出发,分析了混频器设计中的关键技术,如噪声系数、变频损耗、动态范围、隔离度、混频失真等对接收机性能的影响,并从工程角度出发,指出在工程设计中应注意的要点。本文所得结论在工程应用中得到了验证。     

大坝安全监测贫信息的灰模型

根据灰理论利用大坝安全监测中的贫信息，建立了灰色关联度的GM(1，N)状态模型。对某钢筋混凝土平板坝的水平位移分析结果表明，在大坝监测资料系列较短的情况下，运用该模型可为评价大坝安全状况提供依据。     

气顶油气藏水力深穿透射孔数值模拟

运用油藏数值模拟的方法 ,采用某油田实际油藏生产参数 ,研究了水力深穿透井射开程度及射开位置对有气顶油气藏开采效果的影响。研究表明 ,对于气顶油气藏 ,射开程度应小于 30 % ,避气高度应大于 70 %。     

用遗传算法的兼容度极大化模型选优水污染治理方案

采用不同评价方法对水污染治理的16种初选方案进行排序选优,得到不同评价结果,为克服各单个评价方案的片面性,充分挖掘各评价方案包含的信息,提出了基于实数编码加速遗传算法(RAGA)的兼容度极大化模型(RAGA-CDMM)对各单个评价方案进行组合,得到一个最优评价方案。结果表明:RAGA-CDMM得到的最优评价方案,结果更为合理可靠,为决策者进行"多中选好"提供了科学的依据;利用RAGA-CDMM可直接根据各单个评价方案的评价结果数据来确定各评价方案的权重,避免了主观赋权的不足;RAGA-CDMM简便可行,适用性和可操作性强,具有推广应用价值。